Tissue transglutaminase antibody IgA level (tTG) is an excellent screening test for celiac disease in the presence of adequate IgA levels. Most labs while screening for Celiac disease (CD) will do the IgA levels automatically. However the serological test is not a diagnostic test.
Vohra, Pankaj; Kalyan Ray Parashette; Rajmohan Dharmaraj; Angela Deubel; Richardo Castillo; and Jacqueline Fridge. "All tTG positive patient do not have celiac disease." (2018). https://digitalrepository.unm.edu/peds_pubs/161